WordNet sense 1 (a slight wetness):

dampness, moistness

WordNet sense 2 (slightly wet):

moist, dampish

WordNet sense 3 (deaden (a sound or noise), especially by wrapping):

dampen, dull, muffle, mute, tone down

WordNet sense 4 (make vague or obscure or make (an image) less visible):

deaden

WordNet sense 5 (lessen in force or effect):

break, soften, weaken